The use of hydraulic systems to provide multiple consumers is well known. Typically, each consumer may utilise a separate circuit that is supplied from a common source of hydraulic power. However, in more sophisticated systems, multiple independent circuits are established, each with its own source of hydraulic power. The integration of such a system into a design envelope is of paramount concern to ensure that the resultant transmission is compact and does not inhibit the versatility of the device in which it is being used.
More sophisticated and versatile systems use variable capacity hydraulic machines and therefore require adjustment mechanisms and control circuits for the mechanisms. Higher horsepower systems will also use rotating machines with a rotating barrel and axially sliding pistons acting against a stationary swashplate. These machines therefore have a number of inter-relating components that are supported within a housing. The integration of several such machines requires the ability to connect the mechanical and hydraulic power supplies as well as the control functions while maintaining the structural integrity of the machine.
U.S. Pat. Nos. 4,132,278 and 4,129,192 to Todeschini show arrangements of hydraulic machines that are integrated in to the structural envelope of a vehicle. However, in these arrangements the machines are mounted within the overall structure as self contained units so that individual housings must provide the structural support for the components. This makes the overall envelope larger and increases the weight of the unit in which the machines are incorporated.
It is therefore an object of the present invention to provide an arrangement for multiple hydraulic sources that meets the above objectives.